<?php

if (! defined('BASEPATH'))
    exit('No direct script access allowed');

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package CodeIgniter
 * @author ExpressionEngine Dev Team
 * @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license http://codeigniter.com/user_guide/license.html
 * @link http://codeigniter.com
 * @since Version 1.0
 * @filesource
 *
 */
    
// ------------------------------------------------------------------------

/**
 * Trackback Class
 *
 * Trackback Sending/Receiving Class
 *
 * @package CodeIgniter
 * @subpackage Libraries
 * @category Trackbacks
 * @author ExpressionEngine Dev Team
 * @link http://codeigniter.com/user_guide/libraries/trackback.html
 */
class CI_Trackback
{

    var $time_format = 'local';

    var $charset = 'UTF-8';

    var $data = array(
            '',
            'title' => '',
            'excerpt' => '',
            'blog_name' => '',
            'charset' => ''
    );

    var $convert_ascii = TRUE;

    var $response = '';

    var $error_msg = array();

    /**
     * Constructor
     *
     * @access public
     */
    public function __construct ()
    {
        log_message('debug', "Trackback Class Initialized");
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Send Trackback
     *
     * @access public
     * @param
     *            array
     * @return bool
     */
    function send ($tb_data)
    {
        if (! is_array($tb_data)) {
            $this->set_error('The send() method must be passed an array');
            return FALSE;
        }
        
        // Pre-process the Trackback Data
        foreach (array(
                'url',
                'title',
                'excerpt',
                'blog_name',
                'ping_url'
        ) as $item) {
            if (! isset($tb_data[$item])) {
                $this->set_error('Required item missing: ' . $item);
                return FALSE;
            }
            
            switch ($item) {
                case 'ping_url':
                    $$item = $this->extract_urls($tb_data[$item]);
                    break;
                case 'excerpt':
                    $$item = $this->limit_characters(
                            $this->convert_xml(
                                    strip_tags(stripslashes($tb_data[$item]))));
                    break;
                case 'url':
                    $$item = str_replace('&#45;', '-', 
                            $this->convert_xml(
                                    strip_tags(stripslashes($tb_data[$item]))));
                    break;
                default:
                    $$item = $this->convert_xml(
                            strip_tags(stripslashes($tb_data[$item])));
                    break;
            }
            
            // Convert High ASCII Characters
            if ($this->convert_ascii == TRUE) {
                if ($item == 'excerpt') {
                    $$item = $this->convert_ascii($$item);
                } elseif ($item == 'title') {
                    $$item = $this->convert_ascii($$item);
                } elseif ($item == 'blog_name') {
                    $$item = $this->convert_ascii($$item);
                }
            }
        }
        
        // Build the Trackback data string
        $charset = (! isset($tb_data['charset'])) ? $this->charset : $tb_data['charset'];
        
        $data = "url=" . rawurlencode($url) . "&title=" . rawurlencode($title) .
                 "&blog_name=" . rawurlencode($blog_name) . "&excerpt=" .
                 rawurlencode($excerpt) . "&charset=" . rawurlencode($charset);
        
        // Send Trackback(s)
        $return = TRUE;
        if (count($ping_url) > 0) {
            foreach ($ping_url as $url) {
                if ($this->process($url, $data) == FALSE) {
                    $return = FALSE;
                }
            }
        }
        
        return $return;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Receive Trackback Data
     *
     * This function simply validates the incoming TB data.
     * It returns FALSE on failure and TRUE on success.
     * If the data is valid it is set to the $this->data array
     * so that it can be inserted into a database.
     *
     * @access public
     * @return bool
     */
    function receive ()
    {
        foreach (array(
                'url',
                'title',
                'blog_name',
                'excerpt'
        ) as $val) {
            if (! isset($_POST[$val]) or $_POST[$val] == '') {
                $this->set_error(
                        'The following required POST variable is missing: ' .
                                 $val);
                return FALSE;
            }
            
            $this->data['charset'] = (! isset($_POST['charset'])) ? 'auto' : strtoupper(
                    trim($_POST['charset']));
            
            if ($val != 'url' && function_exists('mb_convert_encoding')) {
                $_POST[$val] = mb_convert_encoding($_POST[$val], $this->charset, 
                        $this->data['charset']);
            }
            
            $_POST[$val] = ($val != 'url') ? $this->convert_xml(
                    strip_tags($_POST[$val])) : strip_tags($_POST[$val]);
            
            if ($val == 'excerpt') {
                $_POST['excerpt'] = $this->limit_characters($_POST['excerpt']);
            }
            
            $this->data[$val] = $_POST[$val];
        }
        
        return TRUE;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Send Trackback Error Message
     *
     * Allows custom errors to be set. By default it
     * sends the "incomplete information" error, as that's
     * the most common one.
     *
     * @access public
     * @param
     *            string
     * @return void
     */
    function send_error ($message = 'Incomplete Information')
    {
        echo "<?xml version=\"1.0\" encoding=\"utf-8\"?" .
                 ">\n<response>\n<error>1</error>\n<message>" . $message .
                 "</message>\n</response>";
        exit();
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Send Trackback Success Message
     *
     * This should be called when a trackback has been
     * successfully received and inserted.
     *
     * @access public
     * @return void
     */
    function send_success ()
    {
        echo "<?xml version=\"1.0\" encoding=\"utf-8\"?" .
                 ">\n<response>\n<error>0</error>\n</response>";
        exit();
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Fetch a particular item
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function data ($item)
    {
        return (! isset($this->data[$item])) ? '' : $this->data[$item];
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Process Trackback
     *
     * Opens a socket connection and passes the data to
     * the server. Returns TRUE on success, FALSE on failure
     *
     * @access public
     * @param
     *            string
     * @param
     *            string
     * @return bool
     */
    function process ($url, $data)
    {
        $target = parse_url($url);
        
        // Open the socket
        if (! $fp = @fsockopen($target['host'], 80)) {
            $this->set_error('Invalid Connection: ' . $url);
            return FALSE;
        }
        
        // Build the path
        $ppath = (! isset($target['path'])) ? $url : $target['path'];
        
        $path = (isset($target['query']) && $target['query'] != "") ? $ppath .
                 '?' . $target['query'] : $ppath;
        
        // Add the Trackback ID to the data string
        if ($id = $this->get_id($url)) {
            $data = "tb_id=" . $id . "&" . $data;
        }
        
        // Transfer the data
        fputs($fp, "POST " . $path . " HTTP/1.0\r\n");
        fputs($fp, "Host: " . $target['host'] . "\r\n");
        fputs($fp, "Content-type: application/x-www-form-urlencoded\r\n");
        fputs($fp, "Content-length: " . strlen($data) . "\r\n");
        fputs($fp, "Connection: close\r\n\r\n");
        fputs($fp, $data);
        
        // Was it successful?
        $this->response = "";
        
        while (! feof($fp)) {
            $this->response .= fgets($fp, 128);
        }
        @fclose($fp);
        
        if (stristr($this->response, '<error>0</error>') === FALSE) {
            $message = 'An unknown error was encountered';
            
            if (preg_match("/<message>(.*?)<\/message>/is", $this->response, 
                    $match)) {
                $message = trim($match['1']);
            }
            
            $this->set_error($message);
            return FALSE;
        }
        
        return TRUE;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Extract Trackback URLs
     *
     * This function lets multiple trackbacks be sent.
     * It takes a string of URLs (separated by comma or
     * space) and puts each URL into an array
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function extract_urls ($urls)
    {
        // Remove the pesky white space and replace with a comma.
        $urls = preg_replace("/\s*(\S+)\s*/", "\\1,", $urls);
        
        // If they use commas get rid of the doubles.
        $urls = str_replace(",,", ",", $urls);
        
        // Remove any comma that might be at the end
        if (substr($urls, - 1) == ",") {
            $urls = substr($urls, 0, - 1);
        }
        
        // Break into an array via commas
        $urls = preg_split('/[,]/', $urls);
        
        // Removes duplicates
        $urls = array_unique($urls);
        
        array_walk($urls, array(
                $this,
                'validate_url'
        ));
        
        return $urls;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Validate URL
     *
     * Simply adds "http://" if missing
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function validate_url ($url)
    {
        $url = trim($url);
        
        if (substr($url, 0, 4) != "http") {
            $url = "http://" . $url;
        }
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Find the Trackback URL's ID
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function get_id ($url)
    {
        $tb_id = "";
        
        if (strpos($url, '?') !== FALSE) {
            $tb_array = explode('/', $url);
            $tb_end = $tb_array[count($tb_array) - 1];
            
            if (! is_numeric($tb_end)) {
                $tb_end = $tb_array[count($tb_array) - 2];
            }
            
            $tb_array = explode('=', $tb_end);
            $tb_id = $tb_array[count($tb_array) - 1];
        } else {
            $url = rtrim($url, '/');
            
            $tb_array = explode('/', $url);
            $tb_id = $tb_array[count($tb_array) - 1];
            
            if (! is_numeric($tb_id)) {
                $tb_id = $tb_array[count($tb_array) - 2];
            }
        }
        
        if (! preg_match("/^([0-9]+)$/", $tb_id)) {
            return FALSE;
        } else {
            return $tb_id;
        }
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Convert Reserved XML characters to Entities
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function convert_xml ($str)
    {
        $temp = '__TEMP_AMPERSANDS__';
        
        $str = preg_replace("/&#(\d+);/", "$temp\\1;", $str);
        $str = preg_replace("/&(\w+);/", "$temp\\1;", $str);
        
        $str = str_replace(array(
                "&",
                "<",
                ">",
                "\"",
                "'",
                "-"
        ), array(
                "&amp;",
                "&lt;",
                "&gt;",
                "&quot;",
                "&#39;",
                "&#45;"
        ), $str);
        
        $str = preg_replace("/$temp(\d+);/", "&#\\1;", $str);
        $str = preg_replace("/$temp(\w+);/", "&\\1;", $str);
        
        return $str;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Character limiter
     *
     * Limits the string based on the character count. Will preserve complete
     * words.
     *
     * @access public
     * @param
     *            string
     * @param
     *            integer
     * @param
     *            string
     * @return string
     */
    function limit_characters ($str, $n = 500, $end_char = '&#8230;')
    {
        if (strlen($str) < $n) {
            return $str;
        }
        
        $str = preg_replace("/\s+/", ' ', 
                str_replace(array(
                        "\r\n",
                        "\r",
                        "\n"
                ), ' ', $str));
        
        if (strlen($str) <= $n) {
            return $str;
        }
        
        $out = "";
        foreach (explode(' ', trim($str)) as $val) {
            $out .= $val . ' ';
            if (strlen($out) >= $n) {
                return trim($out) . $end_char;
            }
        }
    }
    
    // --------------------------------------------------------------------
    
    /**
     * High ASCII to Entities
     *
     * Converts Hight ascii text and MS Word special chars
     * to character entities
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function convert_ascii ($str)
    {
        $count = 1;
        $out = '';
        $temp = array();
        
        for ($i = 0, $s = strlen($str); $i < $s; $i ++) {
            $ordinal = ord($str[$i]);
            
            if ($ordinal < 128) {
                $out .= $str[$i];
            } else {
                if (count($temp) == 0) {
                    $count = ($ordinal < 224) ? 2 : 3;
                }
                
                $temp[] = $ordinal;
                
                if (count($temp) == $count) {
                    $number = ($count == 3) ? (($temp['0'] % 16) * 4096) +
                             (($temp['1'] % 64) * 64) + ($temp['2'] % 64) : (($temp['0'] %
                             32) * 64) + ($temp['1'] % 64);
                    
                    $out .= '&#' . $number . ';';
                    $count = 1;
                    $temp = array();
                }
            }
        }
        
        return $out;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Set error message
     *
     * @access public
     * @param
     *            string
     * @return void
     */
    function set_error ($msg)
    {
        log_message('error', $msg);
        $this->error_msg[] = $msg;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Show error messages
     *
     * @access public
     * @param
     *            string
     * @param
     *            string
     * @return string
     */
    function display_errors ($open = '<p>', $close = '</p>')
    {
        $str = '';
        foreach ($this->error_msg as $val) {
            $str .= $open . $val . $close;
        }
        
        return $str;
    }
}
// END Trackback Class

/* End of file Trackback.php */
/* Location: ./system/libraries/Trackback.php */